Apparatus for applying a modifying ingredient to open-celled polyurethane material

ABSTRACT

An apparatus for applying a modifying ingredient to a mass of open-celled polyurethane foam includes the application of an excess of a liquid solution or dispersion of the modifying ingredient to the mass of foam. A fixed frame mounts a plurality of spaced, generally parallel lower backing rollers. A movable frame is mounted above the fixed frame and carries a plurality of spaced, generally parallel pressure rollers for movement toward and away from the backing rollers. A first adjustment device is provided for lowering the movable frame to move the pressure rollers toward the backing rollers, with the mass sandwiched therebetween. A plurality of second adjustment devices are spaced at locations about the rollers for adjusting the pressure between the backing rollers and the pressure rollers uniformly along the rollers both in a direction transversely to and in the direction of movement of the mass through the rollers.

BACKGROUND OF THE INVENTION

This invention generally relates to apparatus for modifying foamedplastic masses and, more particularly, to an apparatus for applyingmodifying ingredients to a mass of open celled polyurethane foam such asfoam sheets.

Early methods for applying dyes, pigments and other modifyingingredients to open-celled polyurethane foam and other open-celled foamswere based generally upon adhesion of the modifying ingredient to thesurface of the foam, as by painting, or upon physical mixing of themodifying ingredient with the constituents prior the foam formation.

An improved method of applying modifying ingredients to open-celledpolyurethane material is disclosed in my U.S. Pat. No. Re. 31,844 datedMar. 5, 1985 (Reissue of U.S. Pat. No. 4,073,979 dated Feb. 14, 1978)which is assigned to the asignee of the present invention. In thatimproved method, the application of a modifying ingredient, such as adye, pigment, color stabilizer or fire retardant, for example,contemplates applying an excess of a liquid solution or dispersion ofthe modifying ingredient to a mass of the foam, such as a foam sheet. Acontinuous strip of the sheet runs between opposed rollers in a tank ofthe liquid solution or dispersion whereat inhaling action takes placebelow the surface of the liquid so that there is little oppurtunity forthe inhalation of air rather than the liquid. The continuous sheet thenis fed through a set of squeeze rollers placed immediately after thedispersion dye tank where the sheet passes through a pressure nipbetween the rollers, the nip being tight enough to return most of theexcess moisture to the liquid solution or dispersion tank. The pickup ofshade from the dye is a function of the degree of squeeze between therollers. Thereafter, the sheet is passed through a heating station whichcreates a suction to pass through gaseous material entirely through themass containing the remainder of the liquid solution or dispersion torapidly raise the temperature of the entire mass or sheet. Thetemperature is at least as high as the vaporization temperature of theliquid under the ambient condition of operation, and the period ofexposure of the mass to the gaseous material is such that the liquid isvaporized and the modifying ingredient is effectively, simultaneouslyincorporated into the foam in a very short time.

The improved method described above has proven effective for modifyingfoam masses with various ingredients such as dyes, pigments, colorstabilizers and fire retardants, including masses or sheets having athickness greater than about 3/32 inch.

In such applications, the pressure applied by the rollers in the liquidsolution or dispersion tank, some of which are driven, is notnecessarily critical. On the other hand, it has been found that theprior art methods of applying modifying ingredients to such masses ofopen-celled polyurethane foam are ineffective when dealing with certainother modifying ingredients. For instance, if it is desirable to apply amodifying ingredient such as a highly soluble salt to a mass ofopen-celled polyurethane foam, extraordinary pressures are requiredwhile the mass or sheet is passed through the liquid solution ordispersion tank in order to pickup substantially all of the salt in theliquid solution. The problem is magnified when it is necessary to obtainuniform pickup either across the mass or continuous sheet or along thesheet. Conventional or previously known roller assemblies have provedinadequate for use with modifying ingredients such as soluble acid dyesor highly soluble salt, because they either are incapable of applyingthe large pressures necessary in the solution or dispersion tank or theydo not apply sufficiently uniform pressures to obtain a uniformmodification of the foam. In fact, it has been discovered that theamount of pickup of such modifying ingredients, such as highly solublesalts or acid dyes, is a function of the pressure applied to the mass inthe liquid solution or dispersion tank.

This invention is directed to providing a new and improved apparatus forapplying a modifying ingredient to a mass of open-celled polyurethanefoam where high pressures are required for effective and uniform pickupof the modifying ingredient.

DESCRIPTION OF THE DRAWINGS

The features of this invention which are believed to be novel are setforth with particularity in the appended claims. The invention, togetherwith its objects and the advantages thereof, may be best understood byreference to the following description taken in conjuntion with theaccompanying drawings, in which like reference numerals identify likeelements in the figures and in which:

FIG. 1 is a side elevational view of a complete appartus including theliquid dispersion tank and roller assembly of the invention;

FIG. 2 is a fragmentary side elevational view, on an enlarged scale, ofthe roller assembly of the invention, with the pressure rollers andbacking rollers separated;

FIG. 3 is a fragmented side elevational view, on a further enlargedscale, of a portion of the roller assembly, with the rollers applyingpressure to the foam mass; and

FIG. 4 is a top plan view of the roller assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings in greater detail, and first to FIG. 1, alayout of an apparatus, generally designated 10, is illustrated, whichapplies a modifying ingredient to a mass of open-celled polyurethanefoam. The mass is a sheet 12 of foam fed into the apparatus from asupply roll 14 at the front end of the apparatus. The processed foamsheet ultimately is wound onto a take-up roll 16 at the rear end of theapparatus. Supply roll 14 is disposed between opposed walls 18 and issupported on four rollers, the end brackets 20a,20b,20c and 20d thereofbeing visible in FIG. 1. The rollers supported by brackets 20b and 20care driven.

From roll 14, foam sheet 12 passes over a roller represented by endbracket 22 and through fife jaws 24. The jaws sense the lateral positionof foam sheet 12 and, through appropriate controls, move roll 14 on ballbearings 26 to center the roll and thereby center foam sheet 12.

The foam sheet then passes over a roller, represented by end bracket 28,and beneath a conventional dancing roller 30. Through appropriatecontrols, the dancing roller is effective to speed up or slow down thefeeding of foam sheet 12 off of roll 14 to prevent the foam sheet frombuckling as it flows through the apparatus. The foam sheet then passesover a pair of horizontally spaced rollers, represented by end brackets32, and into a liquid dispersion bath or tank and roller assemblystation, generally designated 34. This station incorporates the gist ofthe invention as will be described in greater detail hereinafter.

After excess liquid solution or dispersion is applied to the foam sheetat station 34, the foam sheets pass through the nip between a pair ofdriven pinch rollers 36 which remove the excess liquid. The excessliquid thus removed is returned to the tank at dispersion or solutionstation 34 by means of an inclined trough 38. The foam sheet which nowhas been applied with a modifying ingredient passes from pinch rollers36 and beneath a second dancing roller 40 which, through appropriatecontrols, governs the driven speed of the pinch rollers.

The "modified" foam sheet then passes through an oven, generallydesignated 42, wherein the temperature of the polyurethane foam sheet israised to a point to vaporize the liquid present in the liquid solutionor dispersion. The heating process also accelerates the absorption ofthe modifying ingredient into the polyurethane to permanentlyincorporate the modifying ingredient into the foam. An example of a typeof oven or heating apparatus is shown in my aforesaid U.S. Pat. No. Re.31,844 which is incorporated herein by reference.

Lastly, foam sheet 12 passes from oven 42 beneath a third dancing roller44 and onto takeup roll 16. The dancing roller, through appropriatecontrols, governs the speed of the takeup means journalled between walls46.

As stated above, the invention resides in the dispersion bath and rollerassembly station 34 which is shown in greater detail in FIGS. 2-4 whichnow will be described. Before proceeding, it should be reiterated thatheretofore the pressures between the rollers in the liquid solution ordispersion bath were not of major concern, particularly when applyingmodifying ingredients such as dispersion dyes or pigments. However, ithas been found that if a modifying ingredient such as highly solublesalt or a soluble acid dye is to be applied to the mass or sheet ofopen-celled polyurethane foam, extraordinary pressures are required,particularly if it is desirable to achieve substantially 100% pickup ofthe salt onto and into the polyurethane foam. For instance, pressures ashigh as twenty one tons may be required for effectively applying theliquid salt solution to a two-inch thick foam sheet, with the compressedthickness being on the order of 0.050 inch. A 1/16 inch thick foam sheetmay be required on the order of nine tons of pressure, with a compressedthickness on the order of 0.0018 inch. If conventional roller assembliesheretofore known are used to exert such high pressures, it ispractically impossible to accomplish uniformity of the modifyingingredient throughout the width and length of the foam sheet. In fact,the roller assemblies heretofore known would actually bend or warp undersuch loads, particularly if the pressure is applied at any single givenlocation of the roller assembly. It is to these problems that theinvention is directed.

More particularly, referring to FIGS. 2-4, liquid dispersion bath androller assembly station 34 has fixed frame means including a fixed base48 and an upper fixed plate 50 rigidly supported by overhead fixedframes 52. Four vertical guide posts 54 rigidly interconnect base 48 andupper plate 50 in vertically spaced disposition. The guide posts arelocated in a generally rectangular bounding orientation as best seen inFIG. 4.

Movable frame means, generally designated 56, are journalled by means ofcylindrical sleeves 58 which surround guide posts 54 whereby the movableframe means can move in the direction of double-headed arrow 60 (FIG.2). The movable frame means 56 is of substantial mass and substantialconstruction, and includes a horizontal support plate 62 which is fixedto and rigidified by substantial I-beams 64 above the plate. The I-beamsare in a diagonally crossing configuration as shown in FIG. 4. Sleeves58 are fixed to the underside of support plate 62 by means of bolts 66whereby the sleeves depend from the underside of the support plate,surrounding guide posts 54, to guide the vertical movement of movableframe means 56 toward and away from fixed base 48.

Four elongated backing rollers 68 are journalled on and between endframe portions 70 fixed to and projecting upwardly from fixed base 48.Four elongated pressure rollers 72 are journalled on and between endframe portions 74 depending from the underside of support plate 62 ofmovable frame means 56. The rollers are solid in cross-section and maybe as long as six feet. Pressure rollers 72 are driven by appropriatemeans, such as a chain and sprocket mechanism, for moving polyurethanefoam sheet 12 between backing rollers 68 and pressure rollers 72, asindicated by arrow 76 (FIG. 2). Therefore, it can be seen that four setsof backing rollers 68 and pressure rollers 72 extend transversely acrossthe path of foam sheet 12, with each set of rollers spacedlongitudinally in the direction of movement of the foam sheet. It shouldbe noted at this point that the bath or tank for containing the liquidsolution or dispersion is not illustrated in FIGS. 1-4 so that all ofthe rollers are clearly illustrated. However, the bath is sufficientlydeep so that the natural inhaling action of the foam sheet on the liquidsolution or dispersion between the spaced sets of rollers takes placebelow the surface of the liquid. This is important so that there is nooppurtunity for the inhalation of air rather than the liquid.

First adjustment means are provided for moving movable frame means 56and, therefore, pressure rollers 72 downwardly toward fixed rollers 68to sandwich foam sheet therebetween. More particularly, a centrallylocated jack screw 76 passes through upper fixed frame plate 50 andincludes an enlarged head 78 at the lower distal end thereof. Theenlarged head is received within an enlarged socket 80 formed on the topof support plate 62 of the movable frame means. The jack screw isthreaded through a gear 82 which is mounted within a bracket means 84 onthe top of fixed frame plate 50. Gear 82 thereby can rotate relative tothe jack screw but cannot move longitudinally relative thereto. A handcrank 86 is mounted on bracket means 84 and has a worm gear 88 on theinner distal end thereof in mesh with gear 82. Therefore, rotation ofhand crank 86, through worm gear 88, causes rotation of gear 82 in ahorizontal plane. Since jack screw 36 is threaded through gear 82,rotation of gear 82 effects longitudinal movement of the jack screw inthe direction of double-headed arrow 90 (FIG. 2) to raise and lowermovable frame means 56 and pressure rollers 72. Enlarged socket 80provides a degree of lost motion of the movable frame means and pressurerollers when at their lower limit positions so that the substantial massof the movable frame means applies initial pressure, by weight andgravity, onto the foam sheet which is sandwiched between backing rollers68 and pressure rollers 72.

Cylindrical stop members 92 are fixed to base 48 and surround guideposts 54. A plurality of horseshoe shaped shims 94 may be selectivelypositioned between stop members 92 and sleeves 58 of movable frame means56 to provide an initial increment of adjustment at the four corners ofthe roller assembly in order to achieve uniform roller gap thicknessesand, therefore, uniform pressures along the sets of rollers to therebyprovide uniform application of the modifying ingredient to the foamsheet both transversely to and in the direction of movement of thesheet.

A plurality of second adjustment means are provided at spaced locationsabout the roller assembly for adjusting the pressure between backingrollers 68 and pressure rollers 72 uniformly along the sets of rollersboth transversely to and in the direction of movement of foam sheet 12.More particularly, four posts 96 are threaded through upper fixed frameplate 50 and include upper polygonal heads 96a to facilitate rotatingthe posts and moving the posts vertically or longitudinally in thedirection of double-headed arrows 98 (FIG. 2). By moving threaded posts96 downwardly, the lower distal ends thereof can be used to applypressure to the top of movable frame means 56 to finally apply andadjust the pressure between pressure rollers 72 and backing rollers 68.However, in order to reduce the length of threaded posts 96, spacerblocks 100 are provided for selective positioning between the respectivelower distal ends of threaded posts 96 and the top of movable framemeans 56, namely the tops of I-beams 64. These spacer blocks arejournalled for pivoting movement about guide posts 54 in the directionof double-headed arrows 102 (FIG. 4) between positions (as shown)beneath threaded posts 96 to the position shown in phantom at thebottom, right-hand of FIG. 4 where the spacer blocks are out of the wayof vertical movement of movable frame means 56 by jack screw 76. Lastly,micrometer means 104 are provided alongside threaded posts 96 fordetermining and/or recording the amount of pressure and/or adjustmentaccomplished by the second adjustment means comprising threaded posts96. It should be understood that although four locations are illustratedin the preferred embodiment for applying the final adjustment andpressure application, other locations are contemplated by the inventiondepending upon the numbers, orientation and other structural parametersof the roller assembly.

FIG. 2 shows movable frame means 56 in an elevated condition, withpressure rollers 72 spaced upwardly from backing rollers 68. Inoperation, once foam sheet 12 is properly threaded through theapparatus, an operator first will lower movable frame means 56 byrotating hand crank 86. Selective horseshoe shims 94 may have beenpositioned prior to lowering the movable frame means and pressurerollers. Final pressure and/or adjustment then is performed byselectively rotating threaded posts 96 after spacer blocks 100 have beenmoved into position beneath the threaded posts. It should be noted thatthe nips or gaps between the respective sets of rollers are shownexaggerated in FIG. 3 to facilitate the illustration. Gaps on the orderof 0.0018 inch for 1/16 inch thick foam and 0.050 inch for two inchthick foam are typical in order to achieve the pressures required formodifying ingredients such as highly soluble salts.

It will be understood that the invention may be embodied in otherspecific forms without departing from the spirit or centralcharacteristics thereof. The present examples and embodiments,therefore, are to be considered in all respects as illustrative and notrestrictive, and the invention is not to be limited to the details givenherein.

I claim:
 1. An apparatus for applying a modifying ingredient to a massof open-celled polyurethane foam, comprising:means for applying anexcess of a liquid solution or dispersion of said modifying ingredientto the mass of foam; and means for squeezing the mass to remove most ofthe excess liquid, including fixed frame means mounting backing rollersmeans and movable frame means carrying pressure roller means formovement toward and away from the backing roller means, singular firstadjustment means for moving the movable frame means and, thereby, thepressure roller means toward the backing roller means to sandwich themass therebetween, and a plurality of second adjustment means at spacedlocations about the roller means for adjusting the pressure between thebacking roller means and the pressure roller means uniformly along theroller means.
 2. An apparatus for applying a modifying ingredient to amass of open-celled polyurethane foam, comprising:means for applying anexcess of a liquid solution or dispersion of said modifying ingredientto the mass of foam; and means for squeezing the mass to remove most ofthe excess liquid, including fixed frame means mounting a plurality ofspaced, generally parallel backing rollers, movable frame means mountedabove the fixed frame means and carrying a plurality of spaced,generally parallel pressure rollers for movement toward and away fromthe backing rollers, singular first adjustment means for lowering themovabe frame means to move the pressure rollers toward the backingrollers to sandwich the mass therebetween, and a plurality of secondadjustment means at spaced locations about the roller means foradjusting the pressure between the backing roller means and the pressureroller means uniformly along the roller means.
 3. The apparatus of claim2 wherein said movable frame means is generally rectangular andincluding one of said second adjustment means near each corner thereof.4. The apparatus of claim 2 wherein one of said second adjustment meansis located near each end of each outside roller.
 5. The apparatus ofclaim 2 wherein each said rollers are substantially solid incross-section.
 6. An apparatus for applying a modifying ingredient to amass of open-celled polyurethane foam, comprising:means for applying anexcess of a liquid solution or dispersion of said modifying ingredientto the mass of foam; and means for squeezing the mass to remove most ofthe excess liquid, including fixed frame means mounting backing rollermeans and movable frame means carrying pressure roller means formovement toward and away from the backing roller means, first adjustmentmeans located generally centrally of the roller means for moving thepressure roller means toward the backing roller means to sandwich themass therebetween; and a plurality of second adjustment means at spacedlocations about the roller means for adjusting the pressure between thebacking roller means and the pressure roller means uniformly along theroller means.
 7. An apparatus for applying a modifying ingredient to amass of open-celled polyurethane foam, comprising:means for applying anexcess of a liquid solution or dispersion of said modifying ingredientto the mass of foam; and means for squeezing the mass to remove most ofthe excess liquid, including fixed frame means mounting backing rollermeans and movable frame means mounted above the fixed frame means andcarrying pressure roller means for movement toward and away from thebacking roller means, first adjustment means for lowering the movableframe means and, thereby, the pressure roller means toward the backingroller means to sandwich the mass therebetween, a plurality of secondadjustment means at spaced locations about the roller means foradjusting the pressure between the backing roller means and the pressureroller means uniformly along the roller means, and vertical guide meansfor guiding movement of the movable frame means and pressure rollermeans.
 8. The apparatus of claim 7 wherein said movable frame means isgenerally polygonal and said vertical guide means comprise telescopingpost and sleeve means generally at the corners of the movable framemeans.
 9. The apparatus of claim 8 wherein one of said plurality ofsecond adjustment means is located near each corner of the polygonalmovable frame means.
 10. The apparatus of claim 9 wherein each saidsecond adjustment means includes vertically adjustable post meansmovable generally parallel to the vertical guide means.
 11. Theapparatus of claim 10 wherein said vertically adjustable post means isthreaded into a fixed frame portion above the movable frame means forapplying downward biasing pressure on the movable frame means.
 12. Theapparatus of claim 11, including spacer means selectively positionablebetweeen the lower distal end of said vertically adjustable post meansand the movable frame means to accomodate initial adjustment by saidfirst adjustment means.
 13. An apparatus for applying a modifyingingredient to a mass of open-celled polyurethane foam, comprising:meansfor applying an excess of a liquid solution or dispersion of saidmodifying ingredient to the mass of foam; and means for squeezing themass to remove most of the excess liquid, including fixed frame meansmounting a plurality of spaced, generally parallel backing rollers,movable frame means mounted above the fixed frame means and carrying aplurality of spaced, generally parallel pressure rollers for movementtoward and away from the backing rollers, first adjustment means forlowering the movable frame means to move the pressure rollers toward thebacking rollers to sandwich the mass therebetween, and a plurality ofsecond adjustment means at spaced locations about the roller means foradjusting the pressure between the backing rollers and the pressurerollers uniformly along the roller, said second adjustment meansincluding vertically adjustable post means threaded into a fixed frameportion above the movable frame means for applying downward biasingpressure on the movable frame means.
 14. The apparatus of claim 13,including spacer means selectively positionable between the lower distalend of said vertically adjustable post means and the movable frame meansto accomodate initial adjustment by said first adjustment means.
 15. Anapparatus for applying a modifying ingredient to a mass of open-celledpolyurethane foam, comprising:means for applying an excess of a liquidsolution or dispersion of said modifying ingredient to the mass of foam;and means for squeezing the mass to remove most of the excess liquid,including fixed frame means mounting a plurality of spaced, generallyparallel backing rollers, movable frame means mounted above the fixedframe means and carrying a plurality of spaced, generally parallelpressure rollers for movement toward and away from the backing rollers,first adjustment means located generally centrally of the plurality ofrollers for lowering the movable frame means to move the pressurerollers toward the backing rollers to sandwich the mass therebetween,and a plurality of second adjustment means at spaced locations about theroller means for adjusting the pressure between the backing rollers andthe pressure rollers uniformly along the rollers.
 16. An apparatus forapplying a modifying ingredient to a mass of open-celled polyurethanefoam, comprising:means for applying an excess of a liquid solution ordispersion of said modifying ingredient to the mass of foam; and meansfor squeezing the mass to remove most of the excess liquid, includingfixed frame means mounting a plurality of spaced, generally parallelbacking rollers, movable frame means mounted above the fixed frame meansand carrying a plurality of spaced, generally parallel pressure rollersfor movement toward and away from the backing rollers, first adjustmentmeans for lowering the movable frame means to move the pressure rollerstoward the backing rollers to sandwich the mass therebetween, aplurality of second adjustment means at spaced locations about theroller means for adjusting the pressure between the backing rollers andthe pressure rollers uniformly along the rollers, and vertical guidemeans for guiding movement of the movable frame means and pressurerollers.
 17. The apparatus of claim 16 wherein said movable frame meansis generally polygonal and said vertical guide means comprisetelescoping post and sleeve means generally at the corners of themovable frame means.
 18. The apparatus of claim 17 wherein one of saidplurality of second adjustment means is located near each corner of thepolygonal movable frame means.
 19. The apparatus of claim 18 whereineach said second adjustment means includes vertically adjustable postmeans movable generally parallel to the vertical guide means.
 20. Anapparatus for applying a modifying ingredient to a mass of open-celledpolyurethane foam, comprising:means for applying an excess of a liquidsolution or dispersion of said modifying ingredient to the mass of foam;and means for squeezing the mass to remove most of the excess liquid,including fixed frame means mounting a plurality of spaced, generallyparallel backing rollers, movable frame means mounted above the fixedframe means and carrying a plurality of spaced, generally parallelpressure rollers for movement toward and away from the backing rollers,first adjustment means for lowering the movable frame means to move thepressure rollers toward the backing rollers to sandwich the masstherebetween, a plurality of second adjustment means at spaced locationsabout the roller means for adjusting the pressure between the backingrollers and the pressure rollers uniformly along the rollers, saidsecond adjustment means including vertically adjustable post means forapplying downward biasing pressure on the movable frame means, andlinear micrometer means alongside each said vertically adjustable postmeans.